US2341494A

US2341494A - Shear

Info

Publication number: US2341494A
Application number: US408652A
Authority: US
Inventors: Larkin R Williamson
Original assignee: EW Bliss Co Inc
Current assignee: EW Bliss Co Inc
Priority date: 1941-08-28
Filing date: 1941-08-28
Publication date: 1944-02-08
Anticipated expiration: 1961-02-08

Description

Feb. 8, 1944. R. WILLIAMSON SHEAR Fiied Aug.. 2a

. 5' Sheets-Sheet 1 INVENTOR.

LARKIN R. wlLuAMsoN.

ATTORNEYS Feb.4 8, y1944. L..R. WILLIAMSON I v2,341,494

SHEAR K .Filed Aug. 2,8, 1941 5 Sheets-Sheet 2 A 'Y -3a ATTORNEYS Feb. 8, 1944. R. vwlLLmMsoNA I 2,341,494

SHEAR f me@ Aug. 28, 1941 5 sheets-sheet s INVENTOR LARKIN R. WILLIAMSON ATTORNEYS Patented Feb. 8, 1944 SHEAR Larkin It.' Williamson, Brooklyn, N. Y., assignor to E. W. Bliss Company, Brooklyn, N. Y., a corporation of Delaware Application August 28, 1941, Serial No. 408,652

Claims. '('CL 164-110) The present invention relates to shears for cuting metal pieces of the type, in which a lower knife is mounted on a bed plate and a movable upper knife is mounted on a reciprocating ram. One of the objects of my invention is to provide for a novel ram actuating mechanism in which a clutch and a brake, both controlled by hydraulic pressure, operate and stop the action of a planetary gear which is used for transmission of power to the ram operating eccentric.

Another object of my invention relates to hydraulic hold-down members which form a part in the general combination of my novel metal shears. Further objects will appear hereinafter from the following description taken in connection with the accompanying drawings.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims; the annexed drawings and the following description setting forth in detail certain mechanism embodying the invention, such disclosed means constituting, however, but one of various mechanical forms in which the principle of the invention may be used.

In said annexed drawings:

Fig. 1 is a front elevation of the machine;

Fig. 2 is a side elevation of the same;

Fig. 3 is an enlarged View of some of the parts shown in Fig. 2 with the transmission case removed.

Fig. 4 is a section on line 4-4 of Fig. 3;

Fig. 5 shows a single hold-down member in section;

Fig. 6 is a View partly in section of the transmission and the pump for supplying of liquid under pressure to the hydraulic system;

Fig, 7 is a section on lines 1-1 of Fig. 6;

Fig. 8 is a section on lines 8-8 of Fig. 7;

Fig. 9 is a section on lines 9-9 of Fig. 8;

Fig. 10 is a View of the brake partly in section; and

Fig. 11 is a diagrammatic View of the hydraulic power and control system.

Referring to Figs. 1, 2 and 3, the machine comprises a frame I0 connected at both ends to rolled steel side plates II which serve as a support for a bed plate I2 onto which the metal strip is delivered and upon which it rests while being cut.

Plates II will hereafter be called the bed supf ports. Stops I3 are provided at intervals on said bed plate, thus allowing pieces of predetermined length to be cut.

Bed plate I2 carries at the rear, extending Yover the entire length thereof, a blade I4 rigidly fixed to said plate and slidable therewith in a horizontal plane (from right to left in Fig. 2). The upper edge I5 of this blade is not completely horizontal, but is set at a slight downward angle with the vertical edges. The purpose of this arrangement will be explained below.

The bed plate is mounted in the bed supports I I so as to be horizontally adjustable in order to bring blade I4 into proper position for cooperation with the upper blade I6 which is carried by a ram 12 and will be more fully described later. The means for adjusting the bed plate, best seen in Fig. 3, consists in a block 24 havingan upper portion 25 closely fitted into a socket 21,01? the bed plate and held by a screw 26, and a lower portion 28 mounted between two adjusting knobs 2| having fine threads. which will allow of very accurate adjustment of blade edge I5. Two lock screws I9 are provided for holding the parts in place after adjustment has been made.

The side frame of the machine is formed by two heavy rolled steel plates 30, one at each side of the machine, special means being provided for fastening the bed supports rto said plates in View ofthe high stresses in this part of the machine which arise from the ram pressures. These fastening means are shown in Fig. 4.

As shown in that iigure, the bed plate II is formed with an extension I 6a projecting into a cut-out portion of side plate 30. A connecting member 33 made of specially hardened wear resisting material is passed through holes 32 provided therefor. It is bolted to bed support II by means of a bolt 34. Two

heavy bolts

35 and 36 are usedfor fastening plate 30 and bed support II over air gaps 38 which are provided so as to allow for a certain amount of play in -the connection under heavy thrusts of the ram, since a rigid construction might lead to cracks in the metal. For the same reason, that is, to prevent the beginning of fracture cracks under heavy stresses, the holes 32 are formed with curved rather than sharp angular cross-section.

The upper part of the machine comprises a hold-downplate 40 secured to the side plates 3U by bolts 4I. The hold-down plate carries a series of hold-down members 43 serving the well-known purposes of clamping work down on the bed plate while it is being operated upon. The construction of these hold-down members" is"shown in Fig. 5.

Each of these hold-down members comprises a cylinder made up of two parts 44 `and 45. A piston 4l, also consisting of `two parts, is tted with its rod portion 49 into the cylinder at `48.

The piston head is widened to form a plate 50 with a ring-shaped ridge 5| thereon. Attached to said piston head by means of a bolt 54 is a bottom plate 52 equal in diameter to the piston head and having a wide annular groove 55 formed therein corresponding in contour to the ridge 5|. Said groove 55 houses a packing ring 56 of neoprene or similar oil resistant material. This construction of the piston is intended to make the engagement of the hold-down with the work yieldable to an extent that will compensate unevenness in the surface of said work.

The top of piston 4'1 which is fitted into the upper portion 45 of the cylinder, is formed by a piece 59 having a central recess which engages with a correspondingly shaped extension El of a cap 60, a packing or diaphragm 62 being thus held down on the top 59 of the piston and laterally between cylinder 45 and cap 00. The cap itself is rigidly secured to piston rod 49 vby a strong bolt 65. Ports 66 and 61 are provided for admitting and withdrawing oil under pressure which actuates the `piston 41. One of the ports is normally closed and only opened to eliminate entrapped air. A spring 68 mounted in the cylinder normally keeps the piston in Yretracted position. All the hold-down members 43 are connected to a .common supply pipe as will more fully appear in the description of the hydraulic system in connection with Fig. 11.

Directly behind the hold-down plate 40 a gib 10, called the front gib, is mounted which forms part of the guide for the ram 12. A series of bolts 4| rigidly connect the hold-.down plate, gib T0 and side plates 30, while another series of shorter screws 42 serve for fastening together the gib and the side plate 30. At the rear of the ram 'l2 a gib 13, the back gib, is mounted, fastened to plate 30 by means of bolts '15; this back gib completes the guideway for the ram. In front of the ram a guard or shield 29 (Fig. l) is mounted for protecting the operatoragainst the cutting action of the movable knife. Since guards of similar construction are generally used in the art, the same is not described in detail.

Rigidly secured to the ram 'I2 at the bottom edge thereof is the movable knife blade 16. The lower blade edge 1-`| of this knife is inclined at a slight upward angle to a plane normal to the face of the bed. Thus, when the two blades |4 r and 16 meet their cutting edges l5 and 'Il will not be in line, but they will include an angle as shown in Fig. 3, thus avoiding a scraping action on the metal and providing clearance for the parts. It will be understood that the ram and the movable knife, as illustrated in Fig. '3, are in down position. A large opening 18 in side wall 30 allows the metal sheet to be inserted to its proper position even though wider than the distance between frame members 30.

In order to properly adjust the sheet introducedv for shearing so that it will register with the knife, a back gauge 220 of known construction is provided, which is mounted on rails 22| that are fastened to the side plate 30. The adjustment of said back gauge is accomplished by a nut 222 at each'end of the gauge which is in engagement with a respective threaded bar 223. These latter each carry at the end a bevelled gear 224 which mesh with gears 225 mounted on a shaft 220. This shaft may be rotated by a ratchet (not shown) to adj-ust the gauge back and forth.

The part of the sheet severed by the knife may be removed at the rear of the machine.

On that side of the machine where the motor is located a gear case is mounted for housing the various parts of the ram driving transmission. On the opposite side a brake mechanism, generally designated by 19 is secured to the machine frame. The clutch mechanism as well as the brake mechanism are operated by hydraulic pressure, the former being engaged by application of pressure and the latter being released by the application of pressure. Both mechanisms are coupled to the same main shaft (|01 in Fig. 7).

The ram is driven by a motor 8|, which acts through belting 82 to drive a flywheel pulley 83. 'I'he pulley is journalled on a shaft 84 through which power is transmitted from the motor to the driven parts of the machine by means of the drive mechanism shown in Figs. 6 to 9.

In Fig. 7 the gear case or housing 80 is shown suitably secured to the machine frame 39. The housing is rigidly secured to the frame to eliminate as far as possible any driving strain in the parts with a resultant effect on the life of the machine and its operation. The housing is open at the face remote from the side vplate `30 and is provided with a closely fitted removable cap 85 to seal this opening and support some parts of the mechanism while readily permitting access to the housing. Into the lower portion of the cap 85 is fitted a ball bearing 86 in which is journalled the drive shaft 84.

The shaft 84 has keyed thereto ya pinion 88 which is positioned between the bearings 86 and another bearing |02 in which a reduced part of shaft 84 is journalled. This pinion is in mesh with and drives a large gear 89 which is keyed to a short stub shaft 90 mounted in ball bearings |03 and |04. The former set of bearings are carried in the cap 85 while the latter set are mounted in a portion of the driven mechanism as hereinafter described. The hub and toothed portion of the gear 89 are connected by off-set spokes which prov-ide space for partially mounting over the gear hub hereinafter to be described. A pinion 9| which lies closely against the inner portion of the opening of the gear 89 is likewise keyed to the shaft 90.

The driven shaft of the mechanism which connects with the operative portion of the machine tool is represented at |01. Closely overlying the end of the shaft is a anged bushing |09. The outer portion of the bushing is concentric with the shaft and carries the inner races of a pair of tapered thrust bearings H0. The outer races are received within an enlarged opening formed in an inwardly extending sleeve portion of the gear case. The outer periphery of this sleeve portion in turn closely fits the machine frame 30. To provide a concentric assembly consisting of the shaft |01, the bushing |09, the bearings ||0, the case sleeve and the corresponding opening in the frame 30, the bushing |09 passes within the housing and flares outwardly to form a radial flange ||2. A recess is provided concentric with the shaft |01 at the right-hand face of the flange and this recess carries the outer race of the ball bearing unit |04 heretofore `described.

Three cluster gears 92 are carried by the flange and rotate therewith. Each gear is rotatably mounted on a pin 94, which is reduced in crosssecticn at each end and one end of which is carried in the aforesaid flange ||2. The other end of each pin is carried in a reinforcing plate ||3 in such manner that the three gears are spaced apart and are each in mesh with the pinion 9|. The plate and flange are bolted together by three bolts ||4 and additionally three dowels I|5 are provided to reinforce the bolts in securing the plate and ilange together as an integral unit.

A large internal gear 95 is rotatably mounted on the housing in a raceway formed at (Fig. G). This gear is provided on its inner annular face with teeth 93 which engage each of the pinions 92 and result in the gear 95 being normally slowly rotated by reason of the drive from the pinion 9| which rotates the pinions 92. The mounting of the parts is such that the gear 95 rotates more easily than does the shaft |01 connected with the working parts of the machine. Accordingly, when the machine tool is not being driven, the gear 95, the cluster gear 92 and the pinion 9| are all in rotation while the shaft |01 remains idle. However when the gear 95 is clamped against rotation, the driving force of the pinion 9| rotates the cluster gear thereabout resulting in a drive to the machine parts through the shaft |01.

To drive the ram, a pair of opposed brake shoes are, therefore, urged into clamping relation with the outer annular face of the gear 95. These shoes are slidable in ways |2| in the housing and are each provided on its gear engaging face with suitable friction material |22. The ways |2| extend through the housing which is open at their outer ends to allow insertion of the shoes. Such openings are normally closed by a removable cap having annular anges |24 overlying the ends of the slideways and bolted thereto by bolts |23. In cap |25 a cylinder is formed, in which a piston |28 comprising parts |29 and |30 is slidably mounted. This piston is provided with a packing |3|. Fluid under pressure is admitted through an opening to each of the two cylinders and upon its admission each piston forces a respective shoe with clamping relation with the internal gear 95 to lock the same against rotation.

To limit the outward movement of the parts when the mechanism stands idle, a bolt |38 is provided and mounted in a central boss |39 of the cap |25. At its inner end the bolt engages a clip |40 which may be adjusted inwardly or outwardly to control the amount of return in respective pistons |28 when the pressure is released and the drive is disconnected.

The brake mechanism 19 which is arranged at the other side of the machine frame is illustrated in Fig. 10. The brake has a frame 230 in which a shoe 23| is slidably supported and rigidly connected to a rod 232 of a piston 233. 235 indicates the walls of a cylinder in which the piston 233 is slidably mounted. An opening for admission of oil is designated by 231. Between the shoe 23| and the bottom 238 of the cylinder a spring 239 is mounted which forces the shoe into engagement with the driven members. Upon admission of oil through opening 23? pressure is exerted on piston 233 which counteracts the action of spring 239 and disengages the brake from the rotating members. Thus while the machine is working and the pump operating and circulating oil under pressure through the system, the brake will be inactive. It will only stop the machine after the pump action is temporarily interrupted or definitely terminated.

The parts |81 and |88 of the plunger are held together by a nut |90 which is rigidly secured to the lower part |88 and slidably mounted within the upper part |81. A calibrated spring |9| forces the two pieces apart and makes them move asa unit, until a certain pressure, strong enough to overcome the spring, is reached. A leather cup |92 or otherl packing device is secured to the bottom of plunger |88 by a bolt |93 to prevent leakage of oil inwardly between the plunger and the cylinder walls. A pipe |94 connects the pump with the oil tank 200 from which oil is withdrawn and delivered through a pipe |95 to the accumulator 204 (both tank and accumulator being diagrammatically shown in Fig. 1l).

The action of the pump proceeds until a certain desired pressure is reached. Thereafter the over pressure in the liquid puts the spring out of action thus preventing any further pumping action of the plunger with resultant increase of pressure in the accumulator. When the pressure drops below the amount necessary for the operation of the machine, spring |9| will once more become operative and the pump action will be resumed.

The drive shaft 84 has an end step |96 mounted in ball bearings |91 which are fitted in a sleeve portion 93 of casing 80 and held by a plate |91@ bolted to the shaft. A removablecap |98 lying closely against frame 30 is held in place by a stud |99 and seals the opening of the sleeve 93.

For adjusting the stroke of the ram an eccentric mechanism may be used, which is best seen in the left-hand part of Fig. 7, and in Figs. 8 and 9. An eccentric |60 is formed on shaft |01 and has an eccentric strap |4| mounted thereon, the lower end of which is connected by a pin |42 carried by a yoke |49. The latter is rigidly connected to the ram 12 by means of heavy bolts |44 and |45 and has furthermore a projecting por" tion |59 fitting closely into a machined hole in the ram.

Among the desired features in the eccentric mechanism is the adjustment device for making the stroke of the eccentric strap and thereby the stroke of the ram itself correspond to a desired depth of cut. To this end I have provided a bushing |45 on the eccentric strap |4|, said bushing having a gear formed externally and being itself eccentric. A pinion |43 journalled on a shaft |49 engages with the gear on bushing |45 and serves for adjusting the bushing in a desired position that defines the stroke of the ram. The adjustment of shaft |49 may be made by hand. Fig. 9 shows in greater detail the manner in which the adjustment mechanism is mounted. Shaft |49 carries a bushing |50, on which pinion |48 is mounted, and a second bushing 55| for the support of the eccentric strap |4|. Pinion |48 has a reduced neck portion |53 over which a pipe |54 is fitted which connects this part of the adjusting mechanism through the Width of the machine to a duplicate mechanism on the other side.

By a similar arrangement the main shaft |01 on the left side of the eccentric |09 is connected by means of a central shaft i5! extending through the machine to the other side where the duplicate eccentric mechanism is located. The connection is made by means of a coupling l63 keyed to shaft [01 at ISS and to the continuing central shaft lill at I '55, thus securing these shafts against displacement by rotation while the set screws |63, liia. prevent the coupling from sliding.

A locking device is also provided to x the bushing his in the desired position. This locking device consists in a rack |55, which meshes with the gear on bushing Ult While this is set by the action of pinion E48. After the intended position is reached nuts IEE and 651 are tightened and lock the device and thereby the bushing i136 against further movement.

Referring now to Fig. 1l the hydraulic control system comprises the pump i811 which is driven from motor Bl over pulley B3, by shaft t@ and the transmission described above in connection with Fig. 6. The pump is connected by a pipe m with the oil tank 2&0 from which each suction stroke withdraws oil, through a check valve 25| opening in the upward direction only. The oil is delivered through a similar check valve 2&2 to two valves 265 and 2t`=1`and to an accumulator 2M where pressure is built up. When it is intended to start the hydraulic cycle an operating valve 2M is actuated by a rod 288 from a foot treadle 22 (Fig. l). Oil is then flowing through valve 205 and pipe r to a line o which connects up to the hold-down member 3 by branch lines o1 to o4, causing said members to clamp the work.

By pushing the foot treadle on to the second position a member 22a is engaged which serves to actuate valve 201. This valve operates the brake shoe mechanism 91 over line y, which mechanism controls the coupling of the clutch to establish the ram drive. At the same time oil under pressure is admitted through line w to the brake mechanism 19 which is released thereby. The machine is then ready to perform the shearing operation. After this is done the treadle is allowed to return to its initial position, reversing the action of valves 2N and 261. Vvlhen valve 266 is reversed, the hold-down members are released at the same time and oil is returned through pipe :c to the tank 269, which is under atmospheric pressure, While, owing to the reversal of valve 281, pipe t is shut off and the connection of pipes y and w to the tank opened over line s. The brake mechanism 19 is applied thereby and the rotation of the drive mechanism for the ram is completely stopped.

As already mentioned, a foot treadle is provided ior starting the operation of the machine.

It comprises a plurality or" bars and pivotally i mounted levers which transmit the motion of the treadle over two actuating positions to the valves 2% and 201 in the hydraulic power system just described.

The starting treadle mechanism shown in Fig. 2 comprises a bar 22 extending through the machine frame from one side plate to the other. It is mounted on a lever 2l) which is pivoted on a pin 23. This pin has one end pivotally connected to a lever lli mounted for rocking movement on a shaft l1; the other end of lever I5 is pivoted on a pin i8, to which is also pivoted a rod 208 which connects the operating valve Zot to the starting mechanism. A duplicate mechanism of the one just described is connected to a member 22a and arranged substantially in parallel to the rst mentioned mechanism; it serves for operating valve 201.

In operation the Work is presented on the table below the upper shear. The knives are adjusted in accordance with the thickness of the material to be cut and so is the eccentric'ity of the bushing. The operator then starts the hydraulic system in operation by pressing down the treadle bar 22, to rock the lever IS and moves the rod 208 downwardly actuating the operating valve 205. The actuation of valve 20G initiates the hydraulic cycle by first admitting oil under pressure to the hold-down members which will clamp the work before the movable knife bears on the same. After the work is properly clamped by the holddowns, the workman exerts more pressure on the pedal 22 until the second member 22a becomes engaged, which then operates valve 201 in the manner described above in connection with valve 2%. The machine then works as described above with reference to Fig. 11.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the mechanism herein disclosed, provided the means stated by any ofthe following claims or the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as my invention:

l. In ya shear comprising a reciprocating ram, cutting means on said ram, a hold-down plate, a series of hold-down members mounted on said plate, a clutch for alternately coupling and releasing a ram operating gearing, a brake for completely stopping the machine, and driving means to operate said shears, in combination a hydraulic system comprising a pump, a tank connected to one side of said pump for supply of liquid, an accumulator connected to the other side of said pump for receiving liquid under pressure, means connected to said accumulator and |actuated by the liquid under pressure therefrom for coupling and releasing respectively said hold-down system and said clutch, and means for applying the brake simultaneously with the release of the clutch.

2. In a shear comprising a reciprocating ram, cutting means on said ram, a hold-down plate, a series of hold-down members mounted on said plate, a clutch for alternately coupling and releasing a ram operating gearing, a brake for completely stopping the machine and driving means to operate said shears, in combination a hydraulic system comprising a pump, a tank connected to one side of said pump for supply of liquid, an accumulator connected to the other side of said pump for receiving liquid under pressure, a reversible valve for operating said hold-down system and a second reversible valve for operating said clutch and said brake, said second valve being adapted to cause the release of the -brake when the clutch is applied and the application of the brake when the clutch is released.

3. In a shear comprising a reciprocating ram, cutting means on said ram, a hold-down plate, a series of hold-down? members mounted on said plate, a clutch for alternately coupling and releasing a ram operating gearing, driving means to operate said shears and a brake for stopping the action of the driving means in combination, a hydraulic system comprising a pump, a tank connected to one side of said pump for supply of liquid, an accumulator connected to the other side of said pump for receiving liquid under pressure, a reversible valve actuated by the liquid under pressure for coupling and releasing respectively said hold-down system and asecond reversible valve for coupling said clutch while releasing said brake and for releasing said clutch while applying said brake and a single member for first actuating said first mentioned valve and thereafter actuating said second valve and for reversing said valves in opposite order.

4. In a shear comprising a reciprocating ram, cutting means on said ram, a hold-down plate, a series of hold-down members mounted on said plate, driving means to operate said shears in combination a clutch for alternately coupling and releasing a ram operating gearing mounted at the same side of the shears with said driving means, a pump for building up pressure to operate said clutch and said hold-down mechanism mounted in proximity to said clutch land a brake for completely stopping the driven parts of said shears mounted on the other side of the machine frame.

5. In a shear comprising a reciprocating ram,

cutting means on said ram, a hold-down plate, a series of hold-down members mounted on said plate, driving means to operate said shears in combination a clutch for alternately coupling and releasing a ram operating gearing mounted at the same side of the shears with said driving means, a plump for building up pressure to operate said clutch and said hold-down mechanism mounted in proximity to said clutch and a brake for completely stopping the driven parts of said shears mounted on the other side of the machine frame, said brake becoming active when said clutch is disconnected and inactive when said clutch is connected to said driving means.

LARKIN R. WILLIAMSON.